Tropical Cyclone Report
Hurricane Kyle
(AL11008)
25-29 September 2008
Lixion A. Avila
National Hurricane Center
5 December 2008
Kyle was a category one hurricane on the Saffir-Simpson Hurricane Scale that made landfall in southwestern Nova Scotia.
13
a. Synoptic History
The development of Kyle was associated with a tropical wave that moved off the coast of Africa with some convective organization on 12 September. There was a weak low pressure area associated with the wave and the system moved westward and west-southwestward for a few days. As the tropical wave was approaching the Lesser Antilles, it began to interact with a strong upper-level trough over the eastern Caribbean Sea, resulting in an increase in cloudiness and thunderstorms. The surface area of low pressure became better defined as it crossed the Windward Islands and began to develop a larger surface circulation on 19 September. The low pressure area turned toward the northwest and became separated from the wave, which continued its westward track across the Caribbean Sea. The upper-level trough moved westward and weakened, causing small relaxation of westerly shear and allowing the convection associated with the low to become a little more concentrated. The low was near Puerto Rico on 21 September, and continued drifting northwestward. It then spent two days crossing Hispaniola, producing disorganized thunderstorms and a large area of squalls within a convective band over the adjacent Caribbean Sea. During this period, the system lacked a well-defined circulation center as indicated by reconnaissance and local surface data.
The low moved northeastward away from Hispaniola, and finally developed a well-defined surface circulation center. It is estimated that a tropical depression formed at 0000 UTC 25 September about 100 n mi north of the Dominican Republic. Westerly wind shear kept the center to the west of the convection, but as the shear relaxed further, convective bands began to wrap around the center and the system became a tropical storm at 0600 UTC 25 September.
Kyle then moved on a northward track and gradually intensified, becoming a hurricane at 1200 UTC 27 September about 300 n mi west of Bermuda. Kyle continued moving between north and north-northeastward and reached its peak intensity of 75 knots with a central pressure of 989 mb at 1200 UTC 28 September. Thereafter, the cyclone began to lose tropical characteristics as the convection started to become elongated and asymmetric, but it made landfall as a 65-kt hurricane on the western tip of Nova Scotia just north of Yarmouth at 0000 UTC 29 September. Kyle continued rapidly northward and northeastward, developed a frontal structure and became fully extratropical. It was absorbed by a large extratropical low at 1800 UTC 30 September.
The “best track” chart of the tropical cyclone’s path is given in Fig. 1, with the wind and pressure histories shown in Figs. 2 and 3, respectively. The best track positions and intensities are listed in Table 1[1].
b. Meteorological Statistics
Observations in Kyle (Figs. 2 and 3) include satellite-based Dvorak technique intensity estimates from the Tropical Analysis and Forecast Branch (TAFB) and the Satellite Analysis Branch (SAB), as well as flight-level, stepped frequency microwave radiometer (SFMR), and dropwindsonde observations from flights of the 53rd Weather Reconnaissance Squadron of the U. S. Air Force Reserve Command and NOAA P3 reconnaissance missions. Data and imagery from NOAA polar-orbiting satellites, the NASA Tropical Rainfall Measuring Mission (TRMM), the NASA QuikSCAT, and Defense Meteorological Satellite Program (DMSP) satellites, among others, were also useful in tracking Kyle. Post-analysis of data from a NOAA P3 genesis research mission indicate that by 0000 UTC 25 September the circulation was well-defined enough to classify the system as a tropical depression as indicated in the final best track. However, operational Dvorak classifications did not support tropical depression status at that time.
Ship reports of winds of tropical storm force associated with Kyle are given in Table 2, and selected surface observations from land stations and data buoys are given in Table 3. The ship with call sign HPYE located about 100 n mi south of the developing center of Kyle reported winds of 40 knots at 1000 UTC 25 September. This observation was crucial in determining that Kyle had become a tropical storm by that time. The peak intensity of 75 knots was estimated from data from a dropsonde launched from a reconnaissance aircraft. The estimate of 984 mb minimum pressure of Kyle occurred a little bit after the hurricane reached its peak intensity. The minimum pressure was based on the 44011 NOAA buoy, which reported 987.1 mb and winds of 31 knots as the center of Kyle moved nearby. However, although Kyle’s pressure was still falling, the winds were already decreasing. This has been observed in past systems as they transition to an extratropical low.
c. Casualty and Damage Statistics
The low pressure that preceded Kyle produced torrential rains (up to 30 inches) and numerous flash floods and mud slides in Puerto Rico resulting in six deaths. Winds from Kyle caused minor damage over Nova Scotia primarily in the form of some uprooted trees and broken limbs resulting in power outages. Storm surge and waves produced minor street flooding in Shelburne as well.
d. Forecast and Warning Critique
A description of the weather system from which Kyle originated was included in Tropical Weather Outlook (TWO) products beginning at 1200 UTC 18 September. The possibility of tropical cyclone formation was then included in the TWO issued at 1800 UTC 20 September. This was well in advance about five days prior to genesis. The experimental genesis forecast probability reached the high category (> 50%) at 1200 UTC 21 September but the cyclone did not form within the subsequent 48 hours. In fact, the probabilities decreased to the medium category (20 to 50 %) at 1800 UTC 22 September, but then again increased to the high category at 1200 UTC 23 September, about 36 hours before formation. Advisories were initiated 18 hours after the time of formation estimated in the post-analysis.
A verification of official and guidance model track forecasts is given in Table 4. Average official track errors for Kyle were 32, 44 59, 73, and 68 n mi for the 12, 24, 36, and 72 h forecasts, respectively. The number of forecasts ranged from 12 at 12 h to 2 at 72 h. These errors are lower than the average long-term official track errors (Table 4). Also note in Table 4 that both the European (EMXI) and Geophysical Fluid Dynamic (GFDI) models performed extremely well and their track errors were lower than the average official track errors at most of the time periods.
Average official intensity errors were 4, 4, 3, 3 and 5 kt for the 12, 24, 36, 48 and 72 h forecasts, respectively. For comparison, the average long-term official intensity errors are 7, 10, 12, 14, and 18 kt, respectively. Note that the average official intensity errors are lower than the intensity guidance errors at all forecast times (Table 5).
Watches and warnings associated with Hurricane Kyle are given in Table 5. Given the uncertainty in the forecast track and wind radii, watches and warnings were issued for a portion of the northeast coast of the United States. However, Kyle turned toward the north-northeast with most of the associated weather located north and east of the center. There were no reports of significant weather associated with Kyle along the U.S. northeast coast.
Table 1. Best track for Hurricane Kyle, 25-29 September 2008.
(UTC) / Latitude
(°N) / Longitude
(°W) / Pressure
(mb) / Wind Speed
(kt) / Stage
25 / 0000 / 21.5 / 70.0 / 1005 / 30 / tropical depression
25 / 0600 / 22.0 / 69.4 / 1003 / 35 / tropical storm
25 / 1200 / 22.4 / 68.7 / 1002 / 40 / "
25 / 1800 / 23.1 / 68.4 / 1001 / 40 / "
26 / 0000 / 24.0 / 68.0 / 998 / 45 / "
26 / 0600 / 25.0 / 68.2 / 996 / 50 / "
26 / 1200 / 26.0 / 68.6 / 998 / 50 / "
26 / 1800 / 26.9 / 68.6 / 1000 / 50 / "
27 / 0000 / 28.7 / 68.6 / 998 / 55 / "
27 / 0600 / 29.9 / 69.3 / 996 / 60 / "
27 / 1200 / 31.2 / 69.5 / 996 / 65 / hurricane
27 / 1800 / 33.3 / 69.7 / 995 / 70 / "
28 / 0000 / 35.3 / 69.7 / 995 / 70 / "
28 / 0600 / 37.4 / 69.3 / 992 / 70 / "
28 / 1200 / 39.4 / 68.2 / 989 / 75 / "
28 / 1800 / 41.6 / 66.7 / 984 / 70 / "
29 / 0000 / 43.8 / 66.2 / 985 / 65 / "
29 / 0600 / 45.6 / 65.0 / 990 / 50 / extratropical
29 / 1200 / 47.7 / 63.5 / 994 / 45 / "
29 / 1800 / 48.2 / 62.6 / 999 / 40 / "
30 / 0000 / 48.4 / 61.5 / 1002 / 35 / "
30 / 0600 / 48.2 / 61.0 / 1004 / 30 / "
30 / 1200 / 48.1 / 60.8 / 1005 / 25 / "
30 / 1800 / absorbed
28 / 1800 / 41.6 / 66.7 / 984 / 70 / minimum pressure
28 / 1200 / 39.4 / 68.2 / 989 / 75 / maximum intensity
29 / 0000 / 43.8 / 66.2 / 985 / 65 / landfall near Yarmouth, NS
Table 2. Selected ship reports with winds of at least 34 kt for Hurricane Kyle, 25-29 September 2008.
(°N) / Longitude
(°W) / Wind
dir/speed (kt) / Pressure
(mb)
25 / 1000 / HPYE / 20.3 / 68.1 / 190 / 40 / 1002.0
25 / 1800 / KS049 / 21.9 / 67.3 / 240 / 39
25 / 1900 / H3VS / 24.9 / 67.3 / 180 / 40 / 1007.0
26 / 0000 / P3GY9 / 25.0 / 66.6 / 090 / 35 / 1011.0
26 / 0500 / MKYJ8 / 25.3 / 68.5 / 050 / 45 / 1006.7
26 / 0600 / P3GY9 / 25.8 / 65.7 / 100 / 35 / 1013.0
26 / 0900 / MKYJ8 / 25.1 / 67.8 / 180 / 48 / 1004.3
26 / 1500 / MKYJ8 / 25.7 / 66.2 / 160 / 40 / 1013.3
26 / 1800 / MKYJ8 / 26.2 / 65.4 / 140 / 47 / 1014.5
26 / 2100 / MKYJ8 / 26.4 / 64.6 / 140 / 35 / 1015.6
28 / 2100 / CGUM / 42.9 / 63.5 / 150 / 37 / 1008.8
28 / 2100 / ZCBU3 / 43.9 / 62.1 / 150 / 40 / 1017.0
29 / 0000 / ZCBU3 / 43.6 / 61.3 / 150 / 37 / 1017.8
29 / 0600 / VAAP / 44.9 / 61.4 / 160 / 37 / 1006.9
29 / 1800 / VOCZ / 47.1 / 59.5 / 140 / 35 / 1010.7
Table 3. Selected surface observations for Hurricane Kyle, 25-29 September 2008.
Location / Minimum Sea Level Pressure / Maximum SurfaceWind Speed / Storm surge
(ft)c / Storm
tide
(ft)d / Total
rain
(in) /
Date/
time
(UTC) / Press.
(mb) / Date/
time
(UTC)a / Sustained
(kt)b / Gust
(kt) /
Canada ( provided by Environmental Canada)
Yarmouth, NS / 29/0000 / 988.1 / 28/2200 / 26 / 38 / 1.7 / 1.69
Baccaro Point, NS / 22/2246 / 992.1 / 28/2146 / 52 / 67
Brier Island, NS / 29/0100 / 993.9 / 29/0400 / 33 / 40
Western Head, NS / 29/0200 / 997.0 / 29/0300 / 37 / 55
Lunenburg, NS / 29/0400 / 998.1 / 28/2300 / 35 / 44
McNabs Island, NS / 29/0500 / 1001.5 / 29/0400 / 45 / 55
Halifax Dockyard, NS / 29/0030 / 34
Osborne Head, NS / 29/0600 / 35 / 47
Grand Etang, NS / 29/1100 / 1005.0 / 29/0500 / 36 / 56
Halifax, NS / 1.3
Dartmouth, NS / 1.5
North Cape, PE / 29/1000 / 997.3 / 29/0700 / 34 / 45 / 0.97
Wreckhouse, NF / 29/1800 / 49 / 50
Bon Accord, NB / 2.82
Havre-Saint-Pierre, QU / 2.76
Buoys/C-MAN
41011 Georges Bank, MA
41.1° N 66.6°W / 28/1450 / 994.6 / 28/1550 / 52 / 72
44024
42.3 0°N 65.9°W / 28/2004 / 991.2 / 28/2004 / 47
44753
32.0°N 69.7°W / 29/0500 / 1017.9 / 29/0500 / 39
41048 west of Bermuda
32.0°N 69.7°W / 27/1321 / 999.1 / 27/1217 / 49 / 55
44753
43.60°N 61.3°W / 27/0500 / 1017.9 / 27/0500 / 39
41027 Jonesport, Maine
44.3° N 67.3°W / 29/0050 / 999.1 / 28/2250 / 33 / 40
a Date/time is for sustained wind when both sustained and gust are listed.
b Except as noted, sustained wind averaging periods for C-MAN and land-based ASOS reports are 2 min; buoy averaging periods are 8 min; Canada averaging periods are 10 min.
c Storm surge is water height above normal astronomical tide level.
d Storm tide is water height above National Geodetic Vertical Datum (1929 mean sea level).
Table 4. Track forecast evaluation (heterogeneous sample) for Hurricane Kyle, 25-29 September 2008. Forecast errors (n mi) are followed by the number of forecasts in parentheses. Errors smaller than the NHC official forecast are shown in boldface type.
12 / 24 / 36 / 48 / 72 / 96 / 120
CLP5 / 57 (13) / 135 (11) / 261 ( 9) / 378 ( 7) / 610 ( 3)
GFNI / 26 ( 7) / 48 ( 7) / 69 ( 6) / 66 ( 4)
GFDI / 49 (13) / 86 (11) / 143 ( 9) / 211 ( 7) / 337 ( 3)
HWFI / 40 (13) / 67 (11) / 102 ( 9) / 126 ( 7) / 172 ( 3)
GFSI / 44 (13) / 62 (11) / 100 ( 9) / 131 ( 7) / 185 ( 3)
AEMI / 52 (13) / 90 (11) / 140 ( 9) / 207 ( 7) / 257 ( 2)
NGPI / 47 (12) / 70 (10) / 107 ( 8) / 185 ( 6) / 442 ( 2)
UKMI / 44 (10) / 77 ( 8) / 113 ( 6) / 161 ( 4)
EGRI / 44 (10) / 77 ( 8) / 113 ( 6) / 161 ( 4)
EMXI / 28 (10) / 35 ( 9) / 48 ( 7) / 46 ( 5) / 169 ( 1)
BAMD / 40 (13) / 68 (11) / 119 ( 9) / 205 ( 7) / 432 ( 3)
BAMM / 49 (13) / 89 (11) / 132 ( 9) / 204 ( 7) / 399 ( 3)
BAMS / 75 (13) / 125 (11) / 159 ( 9) / 203 ( 7) / 307 ( 3)
LBAR / 44 (13) / 85 (11) / 155 ( 9) / 231 ( 7) / 393 ( 3)
TVCN / 38 (13) / 56 (11) / 85 ( 9) / 112 ( 7) / 184 ( 3)
GUNA / 37 (10) / 49 ( 8) / 66 ( 6) / 73 ( 4)
FSSE / 35 (12) / 51 (10) / 83 ( 8) / 115 ( 6) / 198 ( 2)
OFCL / 32 (12) / 44 (10) / 59 ( 8) / 73 ( 6) / 68 ( 2)
NHC Official
(2003-2007 mean) / 34.0 (1742) / 58.2 (1574) / 82.2 (1407) / 106.2 (1254) / 154.2 (996) / 207.5 (787) / 272.5 (627)
Table 5. Intensity forecast evaluation (heterogeneous sample) for Hurricane Kyle, 25-29 September 2008. Forecast errors (kt) are followed by the number of forecasts in parentheses. Errors smaller than the NHC official forecast are shown in boldface type.
Forecast Technique / Forecast Period (h) /12 / 24 / 36 / 48 / 72 / 96 / 120
OCD5 / 6.3 (15) / 7.9 (13) / 7.3 (11) / 9.1 ( 9) / 15.6 ( 5)
GHMI / 5.3 (15) / 5.1 (13) / 7.7 (11) / 7.2 ( 9) / 25.8 ( 5)
HWFI / 6.8 (15) / 6.3 (13) / 3.5 (11) / 6.6 ( 9) / 23.2 ( 5)
LGEM / 7.9 (15) / 10.8 (13) / 11.2 (11) / 14.9 ( 9) / 23.2 ( 5)
DSHP / 6.7 (15) / 7.0 (13) / 6.1 (11) / 5.7 ( 9) / 9.4 ( 5)
FSSE / 5.5 (12) / 6.2 (10) / 5.3 ( 8) / 6.7 ( 6) / 8.0 ( 2)
ICON / 6.6 (15) / 6.3 (13) / 3.6 (11) / 5.2 ( 9) / 17.2 ( 5)
OFCL / 4.2 (12) / 4.0 (10) / 3.1 ( 8) / 3.3 ( 6) / 5.0 ( 2)
NHC Official
(2003-2007 mean) / 6.7 (1742) / 10.0 (1574) / 12.3 (1407) / 14.3 (1254) / 18.2 (996) / 19.7 (787) / 21.8 (627)
Table 6. Watch and warning summary for Hurricane Kyle, 25-29 September 2008.